He paid $350 in 1972, and used this four-porthole beauty for his first date with his wife and his first 'Tonight Show' appearance. Our car blogger visited Jay Leno's parking lot to get the scoop.

I visited the Jay Leno Show earlier this week to drive on his “Green Car Challenge” track, following in the footsteps of Drew Barrymore, Rush Limbaugh and Steve Carell. A full post—and video—on that is coming up Monday. But while there I stopped by Leno’s parking space and saw this beautiful vision.

Do you remember how, in Orson Welles’ classic 1941 Citizen Kane, it was all about “Rosebud” -- which turned out to be his childhood sled (sorry if you haven’t seen it, but you should have by now)?

Well, for Jay Leno, “Rosebud” is a 1955 Buick Roadmaster. He bought it when he was a scuffling comic and mechanic circa 1972 for $350. He put it into the routines I remember from local comedy clubs back then. I interviewed him twice during those stopovers, and I seem to recall the Buick coming up there, too. Here’s a look at it on video which I shot this week:

On stage, Leno would talk about cars not having any safety equipment in the 50s. Far from offering seatbelts or collapsing steering columns, the Roadmaster had a hard metal dash and knobs sticking out like knives to impale anyone stupid enough to crash it. The kids were on their own in the cavernous back seat -- sitting on someone’s lap or hanging halfway out the window was fine back then, as I dimly recall.

Leno used the Roadmaster on his first date with his wife, and it carried him to his first appearance on the Tonight Show (in ’77). He says it’s his favorite car to drive, and I can attest that he pilots the thing to work (see photo). The Roadmaster was first restored in 1973, but after 30 years of wear and tear he began to “feel guilty that it was in such bad shape. It’s kind of like falling behind in your child support. It needed more than just a restoration. It had to be better than new.”

And now, though it looks just like any other Buick Roadmaster, it has a 620-horsepower ZZ572 crate engine under the hood. The car was thoroughly gone over. I love this detail: Leno put bigger wheels on the car, and that meant actually having the hubcaps enlarged. A minor detail, but undoubtedly a big expense.

No, the four-porthole Roadmaster isn’t green, though Leno does have a Green Garage you can visit. There are electric cars (including a vintage Detroit Electric), early hybrids and even steam cars in his huge collection—I saw one on display at the Petersen Auto Museum on Monday. But there’s only one Rosebud.